JPH062740Y2 - Groundless stirrer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a groundless stirrer, which adopts an axial gap type canned motor or an axial gap type magnetic coupling. The present invention relates to a structure that prevents air bubbles generated in the agitated liquid from accumulating around the bearing due to the above operation and prevents early wear of the bearing portion due to the air bubbles.

(Prior Art) A groundless stirrer employing an axial gap type canned motor, for example, as shown in FIG. 3, has a stator winding 1 wound around an annularly wound and laminated stator core 1. The stator 3 is separated from the stirring liquid 18 by a non-magnetic partition plate 17, that is, a hollow disk-shaped stator can 4 made of a non-magnetic thin-walled metal, and the rotor core 5 and the rotor conductor are wound and laminated in an annular shape. The rotor 7 composed of 6 and 6 is separated from the stirring liquid 18 by a rotor can 8 composed of a non-magnetic thin metal, and the rotor can 8 and the stator can 4 and a gap 9 between the cans 8 and 4 are separated.
The rotor 7 is disposed so as to face the stator 3 via a magnetic gap 19 composed of the rotor 7, the rotor 7 and the rotor substrate 10 to which the rotor 7 is fixed, and the impeller nut 12 on the rotor substrate 10. A rotating body 13 including a stirring impeller 11 having a stirring blade 11a fastened and fixed is rotatably supported on a stationary shaft 15 protruding from the stator 3 through a bearing 14 mounted on the rotating body 13. Since it is configured, it does not have a shaft sealing part such as gland packing or mechanical seal and has a completely leak-free structure, so that the stirring liquid 18 in the stirring tank 16 does not leak to the outside or the outside air enters the stirring liquid 18. It is most suitable for unfavorable applications, and is much flatter than the groundless stirrer that employs a similar radial leak type canned motor with a completely leak-free structure. If you attach it to the bottom, From the height to the installation foundation,
That is, the installation height is low, and when installing on the side of the stirring tank 16, the installation interval with the adjacent device can be shortened,
It is convenient.

(Problems to be solved by the invention) By the way, the lubrication of the bearing 14 in the glandless agitator shown in FIG. 3 is performed by the self-lubricating method by the agitating liquid 18, that is, the narrow gap 9 is formed in the stator can 4. Due to the weak viscous pumping action that occurs in the narrow gap 9 due to the rotation of the rotor cans 8 facing each other through the rotor, the stirring liquid 18 above the stirring impeller 11 is sucked from the through hole 20 of the impeller nut 12, and the bearing The radial gap 21 formed between the bearing 14 including the spiral groove 14a formed in the inner peripheral surface of the bearing 14 and the bearing sliding counterpart member 15a welded to the surface of the stationary shaft 15 and the lower end surface of the bearing 14. Axial gap 23 between the bearing 14 including the groove 14b and the bearing sliding mating member 22a welded to the surface of the thrust collar 22
To the annular space 24, and from this space 24 through a narrow gap 9 between the stator can 4 and the rotor can 8
Although it flows out to the outer peripheral side of 13 and is circulated in the stirring tank 16, lubrication of the bearing 14 is performed by the stirring liquid 18,
As shown in FIG. 4, when this agitator is attached to the bottom of the agitation tank 16 and water operation is performed for several hours, bubbles 28 are discharged from the through hole 20 of the impeller nut 12 at the moment the agitator is stopped. Was confirmed.

Therefore, the following test was conducted in order to deepen this phenomenon.

[Test 1] As shown in FIG. 4, continuous water operation was performed for 3 hours without providing a baffle plate on the stirring tank 16. In this case, since there is no baffle that prevents the circulation of the stirring liquid 18, the water surface is swirling 25 times.
Occasionally, the lower end of the spiral thread 26 reaches the stirrer and air is sucked into the through hole 20 of the impeller nut 12 while making an abnormal noise, and about 50 cc of air bubbles 28 are discharged when the operation is stopped. Was done.

[Test 2] As shown in FIG. 5, the baffle plate 27 was attached to the stirring tank 16 and the continuous water operation was performed for 3 hours. In this case, baffle
The circulation flow of the agitated liquid 18 is hindered by 27, the number of spirals 25 generated is small, and the maximum depth of the spirals 25 is about 20 mm. However, the bubbles 28 released at the time of operation stop are about 50 cc, which is different from the case of Test 1. It didn't change.

[Test 3] Continuous water operation was performed for 2 hours in the same state as in Test 2. The bubbles 28 released when the operation was stopped were about 25 cc.

[Test 4] In the same state as in Test 2, continuous water operation for 1 hour was performed. No air bubbles 28 were released during shutdown.

[Test 5] In the same state as in Test 2, continuous water operation was performed for 60 hours.
The bubbles 28 released during shutdown were about 50 cc, which was the same as in Test 2.

From the above-mentioned tests, the following can be inferred regarding the difference in the discharge amount depending on the cause of generation of the bubbles 28 and the operating time of the stirrer.

That is, a part of the gas such as air dissolved in the stirring liquid 18 appears in the stirring liquid 18 as bubbles 28 due to the pressure drop generated in the stirring impeller 11 and the temperature rise due to the heat generation of the stirrer. The air bubbles 28 are mixed with the circulating flow as the bearing lubricating liquid, sucked through the through holes 20 of the impeller nut 12 and reach the annular space 24 (in the case of tests 2 to 5), and interfere with the stirring tank 16. If plate 27 is not provided, add stirring liquid in addition to this.
The outside air that is generated in the spiral 25 generated in 18 is sometimes sucked together with the spiral 25 from the through hole 20 of the impeller nut 12 while generating an abnormal noise and reaches the annular space 24 (in the case of test 1), and further the impeller nut. Some of the gas such as air dissolved in the agitated liquid 18 sucked from the through holes 20 of 12 has a narrow radial gap 21 between the bearing 14 and the stationary shaft 15, and the bearing 14 and the thrust color.
Due to the pressure drop caused by passing through the narrow axial gap 23 between 22 and the temperature rise due to heat generation of the bearing 14, bubbles 28 appear in the stirring liquid 18 and reach the annular space 24, and the bubbles 28 are mixed. Most of the stirring liquid 18 to be discharged flows out to the outer peripheral side of the rotor 13 through the gap 9 due to the viscous pumping action generated in the narrow gap 9 between the rotor can 8 and the stator can 4. The part is the annular space 24 and the stirring liquid 18 and bubbles 28
Due to the gravity separation action of floating the bubbles 28 due to the difference in specific gravity between the agitating liquid 18 and the inner diameter of the stirring liquid 18 on the outer diameter side of the annular space 24 due to the centrifugal force and the specific gravity difference accompanying the rotation of the rotating body 13. The bubbles 28 are separated to the side and subjected to a centrifugal separation action, and as shown in FIG. 6, the separated bubbles 28 are accumulated in the upper part inside the annular space 24, and as shown in FIG. To
When a certain amount of air bubbles 28 are retained in the annular space 24 (this amount is determined by the shape and size of the annular space 24, the flow rate of the circulating flow as the bearing lubricating liquid, the rotation speed of the rotating body 13, and the like. Further, the bubbles 28 above the rotor flow through the narrow gap 9 between the rotor can 8 and the stator can 4 together with the circulating flow.
It flows out toward the outer peripheral direction of 13, and only a certain amount of the bubbles 28 are retained in the annular space 24 (from the comparison between the test 2 and the test 5).

When the operating time is short and the boundary surface between the bubbles 28 and the agitated liquid 18 in the annular space 24 at the time of stop is above the contact surface between the bearing 14 and the thrust color 22 as shown in FIG. Since all of the bubbles 28 are contained in the upper portion of the annular space 24, the through hole 20 of the impeller nut 12 is provided when the stirrer is stopped.
Although not discharged from the case (in the case of test 4), the operating time becomes long and the bubbles 28 and the agitated liquid in the annular space 24 at the time of stoppage
When the boundary surface with 18 is lower than the contact surface between the bearing 14 and the thrust collar 22 as shown in FIG. 9, the bubbles 28 above the contact surface when the agitator is stopped form the annular space 24. Air bubbles that are contained in the upper part of the
Due to the buoyant force due to the difference in specific gravity between the agitated liquid 18 and the bubbles 28, the bearing 28 passes through the axial gap 23 between the bearing 14 and the thrust collar 22 and the bearing 14
And the radial gap 21 between the stationary shaft 15 and the stationary shaft 15
The impeller nut 12 is discharged from the through holes 20 of 12 to the upper side of the stirrer (in the case of test 3), and when the operation time is further prolonged.
The amount of emission from the through hole 20 of the
It reaches a maximum when the operation time for retaining the above-mentioned fixed amount of air bubbles 28 in 24 is reached, and the discharge amount is the same even if the operation time becomes longer (from test 2 and test 5).

In the above test, the bubbles 28 from the through hole 20 of the impeller nut 12 are, after the power supply to the agitator is cut off, from immediately before the stop of the rotating body 13 rotating by inertia to immediately after the stop. It was confirmed that it was released.
The viscous pump action is generated while the rotor is rotating even at a low speed, and the stirring liquid 18 is sucked from the through hole 20 of the impeller nut 12 and the radial gap 21 between the bearing 14 and the stationary shaft 15
It is circulated by flowing out to the outer peripheral side of the rotor 13 through an axial gap 23 between the thrust collar 22 and the thrust collar 22 and a narrow gap 9 between the rotor can 8 and the stator can 4, and this circulating flow is generated by the bearing 14 Since the bubbles 28 in the annular space 24 are prevented from levitating in the radial gap 21 by the force of descending the radial gap 21 between the stationary shaft 15 and the stationary shaft 15, the action of the circulating flow is eliminated. Only immediately before the stop of 13 is the bubble 28 in the annular space 24 passed through the axial gap 23 between the bearing 14 and the thrust collar 22 to levitate in the radial gap 21 between the bearing 14 and the stationary shaft 15, and the impeller nut. It seems that the gas is discharged from the 12 through holes 20 to the upper side of the stirrer.

Thus, when the bubbles 28 are retained in the annular space 24 by the continuous operation of the stirrer for a long time as described above, the bearings are not only activated and stopped by the influence of the bubbles 28, but also during operation.
14 is partially idle, and especially the axial clearance 23 side has poor lubrication, and the bearing 14, thrust collar 22 and stationary shaft 15
There is a risk of causing early wear of the bearing sliding mating members 22a and 15a.

Further, in addition to the groundless stirrer adopting the axial gap type canned motor, a groundless stirrer adopting an axial gap type magnetic coupling, for example, a mounting plate to the stirring tank 16 as shown in FIG. The non-magnetic partition plate 17 having a slightly thick wall also has the stationary shaft 15 integrally formed in the central portion of the partition plate 17, and the stirring blade 11a is integrally welded to the rotor substrate 10 in which the driven-side magnet 29 is embedded. Body 13 this rotating body 1
A driving side rotating plate 32 having a driving side magnet 31 embedded therein is rotatably supported by the stationary shaft 15 mounted on the stationary shaft 15 and disposed at the bottom of the stirring tank 16.
31 is disposed outside the stirring tank 16 so as to face the driven magnet 29 through the partition plate 17, and the drive side rotating plate 32 is integrally projected from the partition plate 17 to the outside of the stirring tank 16. Also fixed in the output shaft 35 of the gearbox 34 attached to the frame 33, in the groundless stirrer configured to be driven via the gearbox 34 by the general-purpose motor 36 attached to the gearbox 34, There were similar problems.

The present invention has been made in view of the above problems, and prevents the bubbles from staying in the space between the stationary portion of the stirrer and the rotating body, and causes the bearing and the bearing to fail due to poor lubrication caused by the bubbles. An object of the present invention is to provide a glandless stirrer that employs an axial gap type canned motor or an axial gap type magnetic coupling having a structure that prevents the sliding counterpart member from being worn out at an early stage.

[Constitution of device]

(Means for Solving the Problems) The structure of the groundless stirrer of the present invention is such that a rotor provided with stirring blades is arranged at the bottom of a stirring tank, and an axial gap type canned via a non-magnetic partition plate. A groundless stirrer that is rotated by a rotating magnetic field of a motor or an axial gap type magnetic coupling, wherein the canned motor is formed between a stationary portion of the stirrer including the non-magnetic partition plate and the rotating body, or A substantially axial degassing hole is formed in the rotor on the inner side of the magnetic gap of the magnetic coupling and on the outer side of the bearing of the stirrer with one end opening and the other end on the stirring blade side. It is formed by drilling.

(Operation) The groundless stirrer according to the present invention is a magnet of an axial gap type canned motor or an axial gap type magnetic coupling formed between a rotating part and a stationary part of the stirrer including a non-magnetic partition plate. Since a substantially axial degassing hole having one end opening in the space on the inner diameter side of the gap on the outer diameter side of the bearing of the stirrer and the other end opening on the stirring blade side is formed in the rotating body, the stirring liquid The bubbles mixed therein are not retained in this space even if separated in the space, and are floated above the agitator from the degassing holes during the agitator operation.

(Example) Next, the Example of this invention is described based on drawing.

FIG. 1 shows an embodiment in which the present invention is applied to the conventional groundless stirrer shown in FIG. 3 which employs an axial gap type canned motor. The description is omitted.

In FIG. 1, the rotating body substrate 10 has the same structure as the rotating body substrate 10.
Is provided with a plurality of degassing holes 37 axially penetrating from the upper surface of the stirring impeller 11 side near the bearing box portion 10a to the lower surface between the rotor 7 and the bearing 14, that is, the stator can 4 Between the stationary portion of the glandless agitator including the non-magnetic partition plate 17 and the rotor 13 and located on the inner diameter side of the magnetic gap 19 between the stator 3 and the rotor 7 and on the outer diameter side of the bearing 14. An axial degassing hole 37 having one end opening in the annular space 24 and the other end opening on the stirring impeller 11 side is formed in the rotating body 13.

According to the embodiment configured in this manner, the bubbles 28 mixed in the circulation flow that is sucked from the through hole 20 of the impeller nut 12, lubricates the bearing 14, and flows out to the outer peripheral side of the rotating body 13, Third
Similar to the conventional example shown in the drawing, the ring-shaped space 24 is subjected to gravity separation and centrifugal separation to be separated and moved to the upper inside of the ring-shaped space 24. Since it floats up to the space 38 between the stirring impeller 11 and the rotating body substrate 10 through the degassing hole 37 and is not retained in the annular space 24, it is of course not necessary to start and stop due to the bubbles 28. Even during operation, the bearing 14 part is partially idled to prevent premature wear of the bearing 14, the thrust collar 22 and the bearing sliding mating members 22a and 15a of the stationary shaft 15 due to poor lubrication.

Also, the groundless stirrer of this example was attached to the bottom of the stirring tank 16 as in FIG. 5, and continuous water operation was performed for 60 hours, but no bubbles were released when the operation was stopped.

Next, when the present invention is applied to the groundless stirrer adopting the axial gap type magnetic coupling shown in FIG. 2, as shown by the broken line in the figure, the non-magnetic partition plate 17 is used.
In the annular space 24 located between the stationary portion of the groundless stirrer including the rotating body 13 and the magnetic gap 19 between the drive-side magnet 31 and the driven-side magnet 29 and on the inner diameter side of the bearing 14 and on the outer diameter side of the bearing 14. By providing the rotating body 13 with an axial degassing hole 37 having one end opened and the other end opened on the stirring blade 11a side, the same effect as that of the above embodiment can be obtained.

The annular space 24 in which one end of the degassing hole 37 is opened in each of the above embodiments is not limited to an annular shape, and includes a stationary portion of a groundless stirrer including a non-magnetic partition plate 17 and a rotating body.
It is only necessary that the space is located on the outer diameter side of the bearing 14 of the agitator on the inner diameter side of the magnetic air gap 19 of the axial air gap type canned motor or the axial air gap type magnet coupling formed with The degassing hole 37 may also be slightly inclined, and in short, it may be formed in a substantially axial direction so that the bubble 28 floats from the space 24.

[Effect of device]

According to the groundless stirrer of the present invention, the magnetic gap of the axial gap type canned motor or the axial gap type magnetic coupling formed between the stationary portion of the stirrer including the non-magnetic partition plate and the rotating body. Since a substantially axial degassing hole having one end opening in the space on the inner diameter side of the agitator on the outer diameter side of the bearing of the agitator and the other end opening on the agitating blade side is formed in the rotating body, The air bubbles mixed in the air will not stay in the space and will float above the agitator from the degassing holes, and premature wear of the bearing portion due to the air bubbles will be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the groundless stirrer of the present invention, FIG. 2 is a sectional view showing another embodiment of the present invention, and FIG. 3 is a sectional view of a conventional groundless stirrer, 4 and 5 are sectional views of the tank device showing the stirring state of the stirring liquid, and FIGS. 6 to 9 are partial sectional views of the stirrer for explaining the generation state of bubbles. 11a ... stirring blade, 13 ... rotor, 14 ... bearing, 16 ... stirring tank, 17 ... non-magnetic partition plate, 19 ... magnetic gap, 24 ... space, 37 ...
Deaeration.

Claims (1)

[Scope of utility model registration request] 1. A rotating body equipped with stirring blades is disposed at the bottom of a stirring tank and is rotated by a rotating magnetic field of an axial gap type canned motor or an axial gap type magnetic coupling via a non-magnetic partition plate. In the groundless stirrer, the canned motor or the magnetic coupling formed between the stationary portion of the stirrer including the non-magnetic partition plate and the rotating body is closer to the inner diameter side than the magnetic gap of the magnetic coupling. A glandless stirrer, characterized in that a substantially axial degassing hole is formed in the rotating body, one end of which opens in a space on the outer diameter side of the bearing and the other end of which opens on the stirring blade side.